Process variations in the manufacturing of light-emitting diodes and other solid-state illumination sources can cause variations in the spectral composition of emitted light. For example, LEDs may be designed to emit light in a band of wavelengths centered at a specific wavelength. Process variations during manufacturing can cause the individual LEDs to emit light in bands that are shifted from the designed-for wavelengths by various amounts. LED manufacturers typically sort LEDs into “bins”. The bins may be defined, for example, based on the chromaticity of the emitted light as well as other factors, such as the intensity of the emitted light. The cost for purchasing LEDs can vary significantly depending upon the bin.
LEDs may be used for illumination in a wide variety of applications. For example, arrays of LEDs may be used as the backlights in computer displays, televisions, and other displays. Arrays of LEDs may also be used as illumination sources in architectural lighting and other fields. In fields where the chromaticity of the light is important, such as in high quality displays, some prior art solutions require LEDs having tightly controlled and/or matched light outputs. This can be expensive. Other prior art solutions require LEDs to be controlled to compensate for deviations in color between different LEDs.
There exist a number of prior art publications relating to the use of light sources with different color characteristics. Examples include:    US 2011/0026256;    US 2006/0227085;    US 2010/0245228;    US 2010/0110098;    US 2010/0072900;    WO 2009/093895;    US 2008/0122832; and,    US 2010/0118057.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.